测试点

#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll n,m,k,x;
ll kpow(int kn,ll k){//kn^k mod n
	ll res=1;
	ll nk=k;
	ll bn=kn%n;
	while(nk){
		if(nk&1) res=res*bn%n;
		bn=bn*bn%n;
		nk=nk>>1;
	}
	return res;
}
int main(){
	cin>>n>>m>>k>>x;
	cout<<(m*(kpow(10,k%n)%n)+x%n)%n;
	return 0;
}