#include using namespace std; int main() { int N,M,i,sw=0,sb=0; cin>>N>>M; if(N%2!=0){return 0;} int A[N][2],B[N][2]; if(1<=N && N<=100000 && 1<=M && M<=100000){ for(i=0;i>A[i][0]>>A[i][1]; if(A[i][0]<0 || A[i][1]<0 || A[i][0]>10000||A[i][1]>10000){return 0;} if(A[i][0]+A[i][1]!=M){return 0;} } } int a; for(i=0;i