#include <cstdio>

const int Nmax = 1000000;

int N;
int T[Nmax], S[Nmax];

int main() {
    freopen("koba.in", "r", stdin);
    freopen("koba.out", "w", stdout);
    
    scanf("%d %d %d %d", &N, T+1, T+2, T+3);
    
    T[1] %= 10; T[2] %= 10; T[3] %= 10;
    
    S[1] = T[1];
    S[2] = S[1] + T[2];
    S[3] = S[2] + T[3];
    for (int i = 4; i <= N; ++i) {
        T[i] = (T[i-1] + T[i-2] * T[i-3]) % 10;
        S[i] = S[i-1] + T[i];
    }
    printf("%d\n", S[N]);
}