//两个程序的

#include<iostream>
using namespace std;

int qiujiecheng(int x){
  int jc=1;
  for(int i=1;i<=x;i++){
    jc=jc*i;
  }
  return jc;
}

int main(){
  int x,s=0;
  for(int i=1;i<=3;i++){
    cin>>x;
	s=s+qiujiecheng(x);
  } 
  cout<<s<<"\n";
  return 0;
}