#include <bits/stdc++.h> #define int long long #define endl '\n' using namespace std; const int maxn = 100000 + 5; const int inf = 1e18; int change(char ch){ if (ch == 'J') return 1; if (ch == 'O') return 2; if (ch == 'I') return 3; return 0; } int pre[maxn][4], n, k; string s; int sech(int l, int r, int type, int val){ int res = 0; while (l <= r){ int mid = (l + r) >> 1; if (pre[mid][type] >= val){ res = mid; r = mid - 1; } else l = mid + 1; } return res; } signed main(){ ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); cin >> n >> k; cin >> s; s = '$' + s; for (int i = 1; i <= n; i++){ for (int j = 1; j <= 3; j++) pre[i][j] = pre[i - 1][j]; pre[i][change(s[i])]++; } int ans = inf; for (int i = 1; i <= n; i++){ int lastJ = sech(1, n, 1, pre[i - 1][1] + k); if (!lastJ or lastJ > n) continue; int lastO = sech(lastJ, n, 2, pre[lastJ - 1][2] + k); if (!lastO or lastO > n) continue; int lastI = sech(lastO, n, 3, pre[lastO - 1][3] + k); if (!lastI or lastI > n) continue; ans = min(ans, lastI - i + 1 - 3 * k); } cout << (ans == inf ? -1 : ans); return 0; }