let input = require('fs').readFileSync('/dev/stdin', 'utf8');

let A = input.split('\n');
A.pop();
A = A.map(v => v.split(/\s/))
  .filter((v, i) => i != 0);
const t = arr => arr.map((col, i) => arr.map(row => row[i]));
const COUNT = t(A)
  .map((v, i) => v.includes('nyanpass') && [...new Set(v)].length == 2 && i + 1)
  .filter(v => v);
console.log(COUNT.length == 1 ? COUNT[0] : -1);