//三个程序

#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 jiechenghe(int n,int m,int h){
  return qiujiecheng(n)+qiujiecheng(m)+qiujiecheng(h);
}

int main(){
  int n,m,h;
  cin>>n>>m>>h;
  cout<<jiechenghe(n,m,h)<<"\n";
  return 0;
}