function Main(input) {
    input = input.split(' ').map(n => parseInt(n, 10));
    x = input[0];
    y = input[1];
    z = input[2];
    cal = (x - z) / (y + z);
    console.log(Math.floor(cal));
}
Main(require('fs').readFileSync('/dev/stdin', 'utf8'));