#include<cstdio>
#define ull unsigned long long
using namespace std;
ull mod;
ull exp(ull e){
    if(e==0)return 1;
    ull temp=exp(e>>1);
    if(e&1)return temp*temp*10%mod;
    else return temp*temp%mod;
}
int main(){
    ull n,m,k,x;
    scanf("%ull%ull%ull%ull",&n,&m,&k,&x);
    mod=n;
    ull ans=(x+m%mod*exp(k))%mod;
    printf("%ull",ans);
    return 0;
}