#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using Pa = pair<ll,ll>; // vector<Pa> event; event.emplace_back(a,b); // 複数要素(複雑なのを含む)->sortしないならclassを作成すべし
using Vll = vector<ll>;    // Vll a(6,0); //要素0~5 初期値0  
using VVll = vector<Vll>;  // VVll G(N+1,Vll(0));  VVll a(5,Vll(3,0));  vector<VVll> G(H+1,VVll(W+1,Vll(5,0)));
#define INF (ll)1<<60 // 10^18 < 1<<60 = 1152921504606846976
#define FOR(i,a,b)  for(ll i=(ll)(a); i<(ll)(b); i++)// a ~ b-1 i++ for
#define FOR_(i,b,a)  for(ll i=(ll)(b)-1; (ll)(a)<=i; i--)//  b-1 ~ a i-- for
#define ALL(a) (a).begin(),(a).end() // min,max,sort,find,lower_bound
#define OI(s) cout<<(s)<<"\n"  // printf("%8.8lf\n",(s));//double 小数点上8桁まで，下8桁まで出力
#define OI2(s0,s1) cout<<(s0)<<" "<<(s1)<<"\n"
#define OI3(s0,s1,s2) cout<<(s0)<<" "<<(s1)<<" "<<(s2)<<"\n"
#define OI4(s0,s1,s2,s3) cout<<(s0)<<" "<<(s1)<<" "<<(s2)<<" "<<(s3)<<"\n"
#define OIV(a) for(ll i=0;i<(a).size();i++){if((a)[i]==INF){cout<<"I"<<" ";}else {cout<<(a)[i]<<" ";}} cout<<""<<"\n"
#define OIVV(a) for(ll i=0;i<(a).size();i++){for(ll j=0;j<(a[i]).size();j++){if((a)[i][j]==INF){cout<<"I"<<" ";}else {cout<<(a)[i][j]<<" ";}}cout<<" "<<"\n";}

int main(){
    ll N,H,W;
    cin>>N>>H>>W;

    ll ax=0,ay=0;
    ax=(N-1)*(H-1);
    ay=(N-1)*(W-1);
    OI(ax+ay);

    return 0;
}