#include <cstdio>
#include <cmath>
#include <cstring>
#include <algorithm>
#define N 100010
using namespace std;
int d , root , g[N];
char str[10];
struct data
{int p[2] , mx[2] , mn[2] , sum , c[2];bool operator<(data a)const {return p[d] == a.p[d] ? p[d ^ 1]< a.p[d ^ 1] : p[d] < a.p[d];}
}a[N];
void pushup(int x)
{int l = a[x].c[0] , r = a[x].c[1];a[x].mx[0] = max(a[x].p[0] , max(a[l].mx[0] , a[r].mx[0]));a[x].mx[1] = max(a[x].p[1] , max(a[l].mx[1] , a[r].mx[1]));a[x].mn[0] = min(a[x].p[0] , min(a[l].mn[0] , a[r].mn[0]));a[x].mn[1] = min(a[x].p[1] , min(a[l].mn[1] , a[r].mn[1]));a[x].sum = a[l].sum + a[r].sum + 1;
}
int build(int l , int r , int now)
{int mid = (l + r) >> 1;d = now , nth_element(a + l , a + mid , a + r + 1);a[mid].c[0] = a[mid].c[1] = 0;if(l < mid) a[mid].c[0] = build(l , mid - 1 , now ^ 1);if(r > mid) a[mid].c[1] = build(mid + 1 , r , now ^ 1);pushup(mid);return mid;
}
void insert(int &k , int x)
{if(!k) k = x;else if(a[x] < a[k]) d ^= 1 , insert(a[k].c[0] , x);else d ^= 1 , insert(a[k].c[1] , x);pushup(k);
}
int judge(int k , int x1 , int y1 , int x2 , int y2)
{if(!k || a[k].mx[0] < x1 || a[k].mx[1] < y1 || a[k].mn[0] > x2 || a[k].mn[1] > y2) return -1;if(a[k].mn[0] >= x1 && a[k].mn[1] >= y1 && a[k].mx[0] <= x2 && a[k].mx[1] <= y2) return 1;return 0;
}
int query(int k , int x1 , int y1 , int x2 , int y2)
{int tmp = judge(k , x1 , y1 , x2 , y2);if(tmp == 1) return a[k].sum;if(tmp == -1) return 0;int ans = (a[k].p[0] >= x1 && a[k].p[1] >= y1 && a[k].p[0] <= x2 && a[k].p[1] <= y2);return ans + query(a[k].c[0] , x1 , y1 , x2 , y2) + query(a[k].c[1] , x1 , y1 , x2 , y2);
}
int main()
{a[0].mx[0] = a[0].mx[1] = -1 << 30 , a[0].mn[0] = a[0].mn[1] = 1 << 30;int n , m , i , x , y;scanf("%d%d" , &n , &m);for(i = 1 ; i <= n ; i ++ ) scanf("%d" , &g[i]) , a[i].p[0] = i - g[i] , a[i].p[1] = i + g[i];root = build(1 , n , 0);for(i = 1 ; i <= m ; i ++ ){scanf("%s%d%d" , str , &x , &y);if(str[0] == 'M') g[x] = y , a[++n].p[0] = x - y , a[n].p[1] = x + y , insert(root , n);else printf("%d\n" , query(root , x - g[x] - y , x + g[x] - y , x - g[x] + y , x + g[x] + y));}return 0;
}