if (pos == BUF_SIZE) {

memmove(input, input + pos, sizeof(char) * (BUF_SIZE - pos));

fread(input + BUF_SIZE - pos, sizeof(char), sizeof(char) * pos, stdin);

pos = 0;

}

ensureCapacity();

while (isspace(input[pos])) {

++pos;

}

bool sign = false;

if (input[pos] == '-') {

sign = true;

++pos;

}

int res = 0;

while (isdigit(input[pos])) {

res = res * 10 + input[pos] - '0';

++pos;

}

return sign ? -res : res;

ensureCapacity();

while (isspace(input[pos])) {

++pos;

}

return input[pos++];