function f(str) {
let count = 0;
let findCount = function (str) {
for (let i = 0; i < str.length - 1; i++) {
if(str[i] === str[i+1]) {
str = str.slice(0, i) + str.slice(i+2);
count++;
return findCount(str);
}
}
return;
}
findCount(str);
console.log(count);
}
f('12344321')