#include using namespace std; typedef long long ll; typedef unsigned long long ull; typedef pair P; typedef pair P3; typedef pair PP; constexpr ll MOD = ll(1e9 + 7); constexpr int IINF = INT_MAX; constexpr ll LLINF = LLONG_MAX; constexpr int MAX_N = int(1e5) + 5; constexpr double EPS = 1e-9; constexpr int di[] = {0, 1, 0, -1}, dj[] = {1, 0, -1, 0}; #define REP(i, n) for (int i = 0; i < n; i++) #define REPR(i, n) for (int i = n; i >= 0; i--) #define SORT(v) sort((v).begin(), (v).end()) #define SORTR(v) sort((v).rbegin(), (v).rend()) #define ALL(v) (v).begin(), (v).end() int main() { ll n, k; cin >> n >> k; vector x(n), a(n); for(int i=0;i> x[i]; } for(int i=0;i> a[i]; } ll l = k-1, r = k-1; for(ll pos = x[r]; r pos) break; } for(ll pos = x[l]; l>0; l--){ pos = min(pos, x[l]-a[l]); if(x[l-1] < pos) break; } cout << r-l+1 << endl; return 0; }