let input = require('fs').readFileSync('/dev/stdin', 'utf8');
const [T, ...X] = input.split(/\s/);
X.pop();
const R = X.every((v, i) => (i == X.length) || (X[i + 1] = v - 1) || (X[i + 1] = v + 1));
console.log(R ? 'T' : 'F');