import sys

class SegTree:
    def __init__(self, op, e, v):
        self._op = op
        self._e = e
        self._n = len(v)
        self._log = (self._n - 1).bit_length()
        self._size = 1 << self._log
        self._d = [self._e] * (2 * self._size)
        for i in range(self._n):
            self._d[self._size + i] = v[i]
        for i in range(self._size - 1, 0, -1):
            self._update(i)

    def _update(self, k):
        self._d[k] = self._op(self._d[2 * k], self._d[2 * k + 1])

    def set(self, p, x):
        p += self._size
        self._d[p] = x
        for i in range(1, self._log + 1):
            self._update(p >> i)

    def get(self, p):
        return self._d[p + self._size]

    def prod(self, l, r):
        sml = self._e
        smr = self._e
        l += self._size
        r += self._size
        while l < r:
            if l & 1:
                sml = self._op(sml, self._d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self._op(self._d[r], smr)
            l >>= 1
            r >>= 1
        return self._op(sml, smr)

ap = (
    (0, 0, 3, 3),
    (0, 1, 2, 3),
    (0, 2, 1, 3),
    (0, 3, 0, 3),
)

def op(l, r):
    l_c0, l_c1, l_x, l_f, l_ans = l
    r_c0, r_c1, r_x, r_f, r_ans = r

    if r_f == -1: return l
    if l_f == -1: return r

    res_c0, res_c1 = r_c0, r_c1
    if r_f in (0, 1): res_c0 += l_c0
    else: res_c1 += l_c0
    if r_f in (0, 2): res_c0 += l_c1
    else: res_c1 += l_c1

    res_x_list = list(l_x)
    for k in range(4):
        res_x_list[ap[l_f][k]] += r_x[k]
    
    res_f = ap[l_f][r_f]
    res_ans = l_ans + r_ans + l_c0 * (r_x[2] + r_x[3]) + l_c1 * (r_x[1] + r_x[3])

    return (res_c0, res_c1, tuple(res_x_list), res_f, res_ans)

def identity_element():
    return (0, 0, (0, 0, 0, 0), -1, 0)

def main():
    input = sys.stdin.readline
    n, que = map(int, input().split())
    s_in = input().strip()

    s = "+" + s_in
    n_pairs = (n + 1) // 2
    
    a = []
    for i in range(n_pairs):
        op_char, val_char = s[2 * i], s[2 * i + 1]
        c0, c1, ans = 0, 0, 0
        x = [0, 0, 0, 0]
        f = 0
        if op_char == '+': f = 3 if val_char == 'T' else 1
        elif op_char == '*': f = 1 if val_char == 'T' else 0
        else: f = 2 if val_char == 'T' else 1
        x[f] += 1
        if val_char == 'T': ans, c1 = 1, 1
        else: c0 = 1
        a.append((c0, c1, tuple(x), f, ans))

    seg = SegTree(op, identity_element(), a)

    for _ in range(que):
        l, r = map(int, input().split())
        l, r = (l - 1 + 1) // 2, (r + 1) // 2
        res_tuple = seg.prod(l, r)
        print(res_tuple[4])

if __name__ == "__main__":
    main()