#include<iostream> int main(){ int b[100],c[20],i,j,m,n,d=0,t,k; scanf("%d %d",&n,&m); for (i=0;i<n;i++){ scanf("%d",&c[i]); } for (i=0;i<m;i++){ scanf("%d",&b[i]); } for (i=0;i<m-1;i++){ for(j=i+1;j<m;j++){ if(b[j]<b[i]){ t=b[i]; b[i]=b[j]; b[j]=t; } } } for (i=0;i<m;i++){ k=0; for(j=0;j<n;j++){ if(b[i]>=c[j]){ c[j]=210; d++; k++; if(k==2) break; } } } printf("%d",d); return 0; }