Help me with this java program please, not accepting any statement and I can't understand the reason

Question

import java.util.*;
public class program{
public static void main(){
Scanner sc=new Scanner(System.in);
String sent="",word="";
char c=' ';
int n=0,l=0,m=0,j=0;
System.out.println("Enter the number of sentences which may be greater than equals to one but less than 4");
n=sc.nextInt();
System.out.println("Enter a paragraph with each sentences either terminating with '.' or '?'");
sent=sc.nextLine();
sent=sent.toUpperCase();
l=sent.length();
for(int i=0;i<l;i++){
c=sent.charAt(i);
if(c=='.'||c=='?')
m+=1;
}
if(n!=m)
System.out.println("The number of sentences typed before is not same with the number");
StringTokenizer st=new StringTokenizer(sent);
while(st.hasMoreTokens()){
word=st.nextToken();
j+=1;
}
System.out.println("Total number of words in the paragraph is:"+j);
}
}

Answer 1

public static void main(String[] args){ //could be?