#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 qiujiechenghe(int h,int x,int m){
  return qiujiecheng(h)+qiujiecheng(x)+qiujiecheng(m);
}



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