#include <stdio.h>

int main(){
    int a,b,c;
    scanf("%d %d %d",&a,&b,&c);
    if(a<0 || a>0 || b>0 || b<0 || c>0 || c<0){
        printf("Invalid input");
    }
    else{
        int res;
        res = (a*b) + (b*c(b+c));
        printf("%d",res);
    }
    return 0;
}