#ifdef ONLINE_JUDGE
#include <bits/stdc++.h>
#else
#include <algorithm>
#include <bitset>
#include <list>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <queue>
#endif

using namespace std;

// lambda : [] (int a, int b) -> bool { body return }
// string r_str = R"(raw string)"

#define mp make_pair
#define mt make_tuple
#define eb emplace_back
#define pb push_back
#define fi first
#define se second
#define LL long long
#define ULL unsigned long long
#define PI (atan(1) * 4)
#define BASE 73
#define NMAX 10000
#define NMAX2 20001
#define MOD1 1000000007
#define ALL(V) (V).begin(), (V).end()
#define ALLR(V) (V).rbegin(), (V).rend()
#define CRLINE Duxar(__LINE__);
#define SHOWME(x) cerr << __LINE__ << ": " << #x << " = " << (x) << endl;
#define ENTER putchar('\n');
#define step(i) (i & (i - 1)) ^ i

int dx4[] = {-1, 0, 1, 0};
int dy4[] = {0, 1, 0, -1};

int dx8[] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dy8[] = {0, 1, 1, 1, 0, -1, -1, -1};

void Duxar(int _this_line) {
#ifndef ONLINE_JUDGE
	printf("\n . . . . . . . . . . . . . Passed line - %d\n", _this_line);
#endif
}

bool AreEqual(double a, double b) {
	return (fabs(a - b) < 1e-10);
}

template <class T>
bool GetNr(T &_value) {
	T _sign = 1;
	char ch;
	_value = 0;
	while(!isdigit(ch = getchar())) {
		if (ch == -1) {
			return false;
		}
		ch == '-' ? _sign = -1 : _sign = 1 ;
	}
	do {
		_value = _value * 10 + (ch - '0');
	} while(isdigit(ch = getchar()));
	_value *= _sign;
	return true;
}

int SumDigit(int x) {
	int sum = 0;
	do {
		sum += x % 10;
		x /= 10;
	} while (x > 0);
	return sum;
}

int SumInt(int a, int b) {
	int ans = 0;
	for (; a <= b; ++a) {
		ans += a;
	}
	return ans;
}

LL A, B;

int main(){
	string fileInput = "sum";
#ifdef INFOARENA
	freopen((fileInput + ".in").c_str(), "r", stdin);
	freopen((fileInput + ".out").c_str(), "w", stdout);
#else
#ifndef ONLINE_JUDGE
	freopen("/Users/duxar/Workplace/Xcode Projects/Selectie/Selectie/input", "r", stdin);
//	freopen("/Users/duxar/Workplace/Xcode Projects/Selectie/Selectie/result", "w", stdout);
#endif
#endif

	LL ans1, ans2, i, j, cnt;
	ans1 = ans2 = 0;
	
	GetNr(A); GetNr(B);
	
	if (A % 2 == 0) {
		++A;
	}
	i = A / 2;
	
	for (i = A / 2; i % 50 <= 49 && A <= B; ++i, A += 2) {
		ans1 += SumDigit(A);
	}
	
	if (A > B) {
		printf("%d\n", ans1);
		return 0;
	}

	int aux = A;
 	ans2 = 0;
	for (i = 0; i < 50; ++i) {
		ans2 += SumDigit(aux);
		aux += 2;
	}
	
	for (; A + 100 <= B; A += 100) {
		ans1 += ans2;
		ans2 += 50;
	}
	
	while (A <= B) {
		ans1 += SumDigit(A);
		A += 2;
	}
	
	cout << ans1 << '\n';
	
	
//	for (i = 1, j = 0, cnt = 0; i <= 1000; i += 2) {
//		ans1 += SumDigit(i);
//		++j;
//		++cnt;
//		printf("%3d ", SumDigit(i));
//		if (j == 5) {
//			printf("\n");
//			j = 0;
//		}
//		if (cnt == 50) {
//			printf("%d\n", ans1);
//			ans1 = 0;
//			cnt = 0;
//		}
//	}
//	printf("\n");
//	for (i = 0; i <= 20; i += 2) {
//		ans2 += SumDigit(i);
////		printf("%d ", SumDigit(i));
//	}
//	printf("%d %d\n", ans1, ans2);
	return 0;
}