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