#include <iostream> #include <string> #include <climits> using namespace std; int main() { int n; string s1, s2, s; cin>>n; cin>>s1>>s2; int prev1 = -1,prev2 = -1,ret = 0x3f3f3f3f; for(int i = 0;i < n;i++){ cin >> s; if(s == s1) // 去找前面最近的s2 { if(prev2 != -1) ret = min(ret, i - prev2); prev1 = i; } else if(s == s2) // 去找前面最近的s1 { if(prev1 != -1) ret = min(ret, i - prev1); prev2 = i; } } //if(ret == 0x3f3f3f3f) cout<<-1<<endl; if(prev1 == -1 || prev2 == -1) cout<<-1<<endl; else cout<<ret<<endl; return 0; }