悬赏关注

#include <bits/stdc++.h>
#define u using namespace std;
#define ll long long
#define s scanf
#define p printf
#define f for
#define re return
#define ii int
#define vv void
u
ii x,y,n;
ii main() {
	cin>>x>>y>>n;
	x--,y--;
	if(!n%10){
		cout<<(n/10)*y;
	}
	else cout<<(n/10)*y+(n%10)*x;
	re 0;
}