Untitled

from sys import stdin
from bisect import * 
input = stdin.readline
N, M = map(int,input().split())
S = input()
R = []
B = []

for idx in range(N):
    if S[idx] == 'R':
        R.append(idx)
    elif S[idx] == 'B':
        B.append(idx)



R_len = len(R) 
B_len = len(B)

for _ in range(M):
    l, r = map(int,input().split()) 

    r_idx_1 = bisect_left(R,l)
    r_idx_2 = bisect_left(R,r)
    # print(r_idx_1,r_idx_2,1212,R)
    
    if( (abs(r_idx_1-r_idx_2)<=1 and r_idx_2 == R_len) or r_idx_1==R_len):
        print(-1)
        continue

    b_idx_1 = bisect_left(B,l)
    b_idx_2 = bisect_left(B,r)
    
    if((abs(b_idx_1-b_idx_2)<=1 and b_idx_2==B_len) or b_idx_1==B_len):
        print(-1)
        continue

    if(b_idx_2 == B_len):
        b_idx_2-=1

    a, b = R[r_idx_1], R[r_idx_1+1]
    c, d = B[b_idx_2-1], B[b_idx_2]
    if(l<=a<b<c<d<=r):
        print(a,b,c,d)
    else:
        print(-1)