let count = p.length,
sum=0, left = 0, right = 0, parray = Array(27).join('0').split('').map(x => parseInt(x));
for (let pc of p) {
parray[pc.charCodeAt() - 97] ++;
}
while (right < s.length) {
if (parray[s[right++].charCodeAt() - 97]-- >= 1) count--; if (count === 0) sum++; if (right - left === p.length && parray[s[left++].charCodeAt() - 97] ++ >= 0) count ++;
}
return sum;
