//作差除100就得到秒数(四舍五入)
var readline = require('readline');
var rl = readline.createInterface({
input : process.stdin,
output : process.stdout
});
rl.on('line', function(line){
// 这道题注意输入数据为一行字符串"123 4577973"
// 需要分割line为C1 C2
cs = line.split(' ');
//split(' ')按' '分割字符串,并返回一个数组
var C1 = cs[0];
var C2 = cs[1];
// C1,C2都为字符串
var C = C2 - C1;
var c = Math.round(C/100);
//js四舍五入取整用round
//取整函数需要Math库
var h = Math.floor(c/3600);
//js向下取整用floor
var m = Math.floor((c - h*60*60) / 60);
var s = c - h*60*60 - m*60;
if (h < 10) { //将一位数的情况处理为两位数字符串,十位为0
h = '0' + String(h);
}
if (m < 10) {
m = '0' + String(m);
}
if (s < 10) {
s = '0' + String(s);
}
var result = h + ':' + m + ':' + s;
console.log(result);
})