const input = require("fs").readFileSync("/dev/stdin", "utf8");
const nums = input.split(' ').map(n => parseInt(n));
const calcNums = [
    nums.reduce((a, b) => a + b),
    nums.reduce((a, b) => a - b),
    nums.reduce((a, b) => a * b),
]

console.log(Math.max(...calcNums));