function main(input) {
    const args = input.split(' ');
    const A = parseInt(args[0], 10);
    const B = parseInt(args[1], 10);
    const C = parseInt(args[2], 10);

    if(B+C <= A ){
        console.log(0);
    }else {
        console.log(B+C-A);
    }
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));
