题解 | #挑7#

const readline = require('readline');

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});
rl.on('line', function (line) {
    const n = Number(line)
    let res = 0
    for(let i = 7; i <= n; i++){
        if(i % 7 === 0 || (i + '').includes('7'))   res++
    }

    console.log(res)
});