Petr stands in line of *n* people, but he doesn't know exactly which position he occupies. He can say that there are no less than *a* people standing in front of him and no more than *b* people standing behind him. Find the number of different positions Petr can occupy.
The only line contains three integers *n*, *a* and *b* (0 ≤ *a*, *b* &lt; *n* ≤ 100).
3 1 1
2
5 2 3
3
5 4 0
1
6 5 5
1
9 4 3
4
11 4 6
7
13 8 7
5
14 5 5
6
16 6 9
10
20 13 17
7
22 4 8
9
23 8 14
15
26 18 22
8
28 6 1
2
29 5 23
24
32 27 15
5
33 11 5
6
37 21 15
16
39 34 33
5
41 27 11
12
42 25 16
17
45 7 43
38
47 16 17
18
49 11 37
38
51 38 39
13
52 29 7
8
56 43 12
13
58 57 28
1
59 12 39
40
62 9 52
53
63 29 44
34
65 30 22
23
66 27 38
39
71 33 53
38
73 14 12
13
73 37 35
36
76 69 44
7
79 25 20
21
81 60 20
21
81 79 14
2
84 0 42
43
88 79 8
9
90 76 59
14
92 2 22
23
94 5 88
89
94 62 48
32
96 22 72
73
100 11 88
89
100 81 91
19
1 0 0
1
#define FNAME ""
 
#ifdef LOCAL
    #define _GLIBCXX_DEBUG
#endif
 
#include <bits/stdc++.h>
 
#define hash padjf9srpi
#define y0 sdkfaslhagaklsldk
#define y1 aasdfasdfasdf
#define yn askfhwqriuperikldjk
#define j1 assdgsdgasghsf
#define tm sdfjahlfasfh
#define lr asgasgash
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define forn(i, n) for (int i = 0; i < (n); i++)
#define fornr(i, n) for (int i = (n) - 1; i >= 0; i--)
#define forab(i, a, b) for (int i = (a); i < (b); i++)
#define gcd __gcd
#define all(a) (a).begin(), (a).end()
  
#ifdef _WIN32
    #define I64 "%I64d"
#else
    #define I64 "%lld"
#endif
 
using namespace std;
 
typedef long long LL;
typedef unsigned long long ULL;
typedef long double LD;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair <int, int> pii;                                                                                                                                                                                      
typedef vector <int> vi;
 
template <class T> T sqr(const T &a) {return a * a;}
 
 
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
 
#ifdef LOCAL
    freopen(FNAME".in", "r", stdin);
    freopen(FNAME".out", "w", stdout);
#endif
 
    int n, a, b;
    scanf("%d%d%d", &n, &a, &b);
    int ans = 0;
    forn(i, n) {
        if (i >= a && n - i - 1 <= b) ans++;
    }
    printf("%d\n", ans);
        
}

