#include using namespace std; using ll = long long; using vll = vector; using vvll = vector; using vvvll = vector; using vvvvll = vector; using vb = vector; using vvb = vector; using vvvb = vector; using vvvvb = vector; using vd = vector; using vvd = vector; using vvvd = vector; #define all(A) A.begin(),A.end() #define ALL(A) A.begin(),A.end() #define rep(i, n) for (ll i = 0; i < (ll) (n); i++) using pqr = priority_queue, vector>, greater>>; template bool chmax(T& p, T q, bool C = 1) { if (C == 0 && p == q) { return 1; } if (p < q) { p = q; return 1; } else { return 0; } } template bool chmin(T& p, T q, bool C = 1) { if (C == 0 && p == q) { return 1; } if (p > q) { p = q; return 1; } else { return 0; } } ll gcd(ll(a), ll(b)) { if (b == 0)return a; ll c = a; while (a % b != 0) { c = a % b; a = b; b = c; } return b; } void warshall_floyd(int n, vvll& d) { for (int k = 0; k < n; k++) { // 経由する頂点 for (int i = 0; i < n; i++) { // 始点 for (int j = 0; j < n; j++) { // 終点 d[i][j] = min(d[i][j], d[i][k] + d[k][j]); } } } } vector fact, factinv, inv; ll mod = 1e9 + 7; void prenCkModp(ll n) { fact.resize(n + 5); factinv.resize(n + 5); inv.resize(n + 5); fact.at(0) = fact.at(1) = 1; factinv.at(0) = factinv.at(1) = 1; inv.at(1) = 1; for (ll i = 2; i < n + 5; i++) { fact.at(i) = (fact.at(i - 1) * i) % mod; inv.at(i) = mod - (inv.at(mod % i) * (mod / i)) % mod; factinv.at(i) = (factinv.at(i - 1) * inv.at(i)) % mod; } } ll nCk(ll n, ll k) { if (n < k) return 0; return fact.at(n) * (factinv.at(k) * factinv.at(n - k) % mod) % mod; } int main() { ll A,B,C,D; cin>>A>>B>>C>>D; if(A!=B){ cout<<(A