#include "bits/stdc++.h" using namespace std; typedef long long ll; typedef long double ld; #define mp make_pair #define pb push_back #define FOR(i,a,x) for(int i=(a);i<(x);i++) #define rep(i,n) FOR(i,0,n) #define xFOR(i,a,x) for(int i=(a);i<=(x);i++) #define xrep(i,n) xFOR(i,1,n) #define sor(v) sort(v.begin(),v.end()) #define rev(s) reverse(s.begin(),s.end()) #define lb(vec,a) lower_bound(vec.begin(),vec.end()) #define ub(vec,a) upper_bound(vec.begin(),vec.end()) #define uniq(vec) vec.erace(unique(vec.begin(),vec.end(),vec.end)) #define mp1(a,b,c) P1(a,P(b,c)) #define all(x) (x).begin(),(x).end() #define debug(X) cout<<"["<<#X<<"]"<= 0 && y >= 0 && xMax > x && yMax > y; } inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; } template inline string toString(const T &a) { ostringstream oss; oss << a; return oss.str(); } template inline T sqr(T x) { return x*x; } const double PI = acos(-1.0); const int dx[8] = { 1, 0, -1, 0, 1, 1, -1, -1 }, dy[8] = { 0, -1, 0, 1, -1, 1, -1, 1 }; const int mod = 1000000007; const int NIL = -1; ll ans; ll a, b; int main() { cin >> a >> b; if (a > b)cout << 2000000000 - b << endl; else cout << a - 1 << endl; return 0; }