solution = False

b = []

def gensubset(i):
    global solution
    if solution:
        return 1
    if i<=(len(L)-1):
        b[i]=False
        gensubset(i+1);
        b[i]=True
        gensubset(i+1);
    else:
        S = 0
        for i in range(len(L)):
           if b[i]:
               S+=L[i]
        if (S%N==0)and(S>0):
            solution = True
            print(sum(b))
            for i in range(len(L)):
                if (b[i]):
                    print i+1,   
            solution=True                            

N = int(raw_input())

L = raw_input()
L = L.split()

for i in range(len(L)):
    L[i]=int(L[i])
    b.append(False)
        
gensubset(0)