#include <bits/stdc++.h>
using namespace std;
#define int long long
int n,a,k,p;
int ksm(int a,int b) {
    int ans=1;
    while(b){
        if(b&1){
            ans=(ans*a)%p;
        }
        a=(a*a)%p;
        b>>=1;
    }
    return ans;
}
signed main(){
    freopen("oeis.in","r",stdin);
    freopen("oeis.out","w",stdout);
    cin>>n>>a>>k>>p;
    if(a==1){
        int ans=0;
        for(int i=1;i<=n;i++){
            ans=(ans+ksm(i,k)%p)%p;
        }
        cout<<ans;
    }
    
    return 0;
}