#include
using namespace std;
#define REP(i,n) for(int i=0;i<(n);++i)
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
class Solution {
public:
string convert(string s, int nRows) {
if (nRows == 1) return s;
string ret = s;
int len = s.length();
int n = nRows * 2;
int idx = 0;
REP(i,nRows) {
for (int j = i; j < len; j += n - 2) {
ret[idx++] = s[j];
int t = j + n - 2 - i - i;
if (t < len && t != j && t != j + n - 2) ret[idx++] = s[t];
}
}
return ret;
}
};
int main() {
Solution s = Solution();
cout << s.convert("PAYPALISHIRING", 3) << endl;
cout << s.convert("A", 1) << endl;
return 0;
}