//In the name of ALLAH
#include<bits/stdc++.h>
using namespace std;


#define optimize() ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define endl '\n'
// User defined sizeof macro
# define my_sizeof(type) ((char *)(&type+1)-(char*)(&type))
#define ll long long int 

int main()

{
    optimize();
    int n,a,b;
    cin>>n>>a>>b;
    
    cout<<n-a+b;













    return 0;
}




#include <bits/stdc++.h>
#include <iostream>
#include <queue>
#include <stack>
#include <vector>
#include <string>
#include <set>
#include <map>
#include <random>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define repp(i,n,m) for (int i = m; i < (n); ++i)
#define repl(i,n) for (long long i = 0; i < (n); ++i)
#define reppl(i,n,m) for (long long i = m; i < (n); ++i)
//#define int long long
using namespace std;
//#include <atcoder/all>
//using namespace atcoder;
using ll = long long;
using ld = long double;
using P = pair<int, int>;
using PI = pair<pair<int,int>,int>;
using PL = pair<long long, long long>;
using PLL = pair<pair<long long, long long>, long long>;
using Pxy = pair<long double, long double>;
using Tiib = tuple<int, int, bool>;
using vvl = vector<vector<ll>>;
const int INF = 1001001007;
const int modd = 1000000007;
const long long modl = 1000000007LL;
const long long mod = 998244353LL;
const ll inf = 1e18;
template <typename AT>
void printvec(vector<AT> &ar){
    rep(i,ar.size()-1) cout << ar[i] << " ";
    cout << ar[ar.size()-1] << endl;
}
template <typename Q>
void printvvec(vector<vector<Q>> &ar){
    rep(i,ar.size()){
        rep(j,ar[0].size()-1) cout << ar[i][j] << " ";
        cout << ar[i][ar[0].size()-1] << endl;
    }
}
template <typename S>
bool range(S a, S b, S x){
    return (a <= x && x < b);
}

void yes(){
    cout << "Yes" << endl;
}

void no (){
    cout << "No" << endl;
}

ll cel (ll a, ll b){
    if (a % b == 0) return a / b;
    else return a / b + 1;
}

ll gcds(ll a, ll b){
    ll c = a % b;
    while (c != 0){
        a = b;
        b = c;
        c = a % b;
    }
    return b;
}

vector<vector<vector<ld>>> dp(101,vector<vector<ld>>(101,vector<ld>(101,-1.0)));

ld sik(int a, int b, int c){
    if (dp[a][b][c] >= 0.0) return dp[a][b][c];
    if (a == 100){
        dp[a][b][c] = 0.0;
        return dp[a][b][c];
    }
    if (b == 100){
        dp[a][b][c] = 0.0;
        return dp[a][b][c];
    }
    if (c == 100){
        dp[a][b][c] = 0.0;
        return dp[a][b][c];
    }
    ld i = a; ld j = b; ld k = c;
    ld ans = i * sik(a+1,b,c) + j * sik(a,b+1,c) + k * sik(a,b,c+1);
    ans /= i + j + k;
    dp[a][b][c] = ans + 1.0;
    return dp[a][b][c];
}

int main(){
    int a, b, c; cin >> a >> b >> c;
    cout << setprecision(20) << sik(a,b,c) << endl;
}