#include<stdio.h>
main()
{
	char fin[100], fout[100];
	for(int t = 1 ; t <= 5 ; t++ )
	{
		sprintf(fin,".%d.in",t);
		sprintf(fout,".%d.out",t);
		freopen(fin,"r",stdin);
		freopen(fout,"w",stdout);
		int n, m, k, a, c, s = 0;
		long long b;
		scanf("%d%d%d%d", &n,&m,&a, &k);
		for( b = n, k-- ; k  ; b=b*m+a, k-- );
	 	printf("%lld", b);
    }
}