function chengji (num1,num2) {
return num1*num2
}
let a = chengji(2 , 3)
console.log(a)
for (let b = 1 ; b <= 100 ; b++ ){
let c=String(b)
let d = c.match(/7/)
console.log(d)
}
for (let month = 4 ; month <= 20 ; month++){
function tuzi(p) {
if(month<=20){
return tuzi(p)*2
}
}
}
console.log(tuzi(1))