题解 | #自守数#

let line

while(line = readline()){
    let num = parseInt(line);
    let count = 0
    for(let i=0;i<=num;i++){
        let power = Math.pow(i,2);
        let str = String(power)
        let idot = String(i)
        if(str.endsWith(idot)){
            count++
        }
    }
    console.log(count)
}