import java.util.Scanner;


public class Main{

	public static void main(String args[]){

		Scanner sc = new Scanner(System.in);

		int n =sc.nextInt();
		int h[]=new int[n];

		int count=0;
		boolean start=false;


		for(int i=0;i<n;++i){
			h[i]=sc.nextInt();
		}

		for(int num=1;num<=100;++num){
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		}

		System.out.println(count);


	}
} import java.util.Scanner; Scanner java.util public class Main{

	public static void main(String args[]){

		Scanner sc = new Scanner(System.in);

		int n =sc.nextInt();
		int h[]=new int[n];

		int count=0;
		boolean start=false;


		for(int i=0;i<n;++i){
			h[i]=sc.nextInt();
		}

		for(int num=1;num<=100;++num){
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		}

		System.out.println(count);


	}
} Main public static void main(String args[]){

		Scanner sc = new Scanner(System.in);

		int n =sc.nextInt();
		int h[]=new int[n];

		int count=0;
		boolean start=false;


		for(int i=0;i<n;++i){
			h[i]=sc.nextInt();
		}

		for(int num=1;num<=100;++num){
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		}

		System.out.println(count);


	} main {

		Scanner sc = new Scanner(System.in);

		int n =sc.nextInt();
		int h[]=new int[n];

		int count=0;
		boolean start=false;


		for(int i=0;i<n;++i){
			h[i]=sc.nextInt();
		}

		for(int num=1;num<=100;++num){
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		}

		System.out.println(count);


	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n =sc.nextInt(); n sc.nextInt() sc.nextInt sc int h[]=new int[n]; h new int[n] n int count=0; count 0 boolean start=false; start false for(int i=0;i<n;++i){
			h[i]=sc.nextInt();
		} int i=0; int i=0; i 0 i<n i n ++i ++i i {
			h[i]=sc.nextInt();
		} {
			h[i]=sc.nextInt();
		} h[i]=sc.nextInt() h[i] h i sc.nextInt() sc.nextInt sc for(int num=1;num<=100;++num){
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		} int num=1; int num=1; num 1 num<=100 num 100 ++num ++num num {
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		} {
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		} start=false start false for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			} int i=0; int i=0; i 0 i<n i n ++i ++i i {
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			} {
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			} if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false; h[i]!=0 h[i] h i 0 {
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				} if(start==false){
						start =true;
						++count;
					} start==false start false {
						start =true;
						++count;
					} start =true start true ++count count h[i]=h[i]-1 h[i] h i h[i]-1 h[i] h i 1 start=false start false System.out.println(count) System.out.println System.out System System.out count String args[] args public class Main{

	public static void main(String args[]){

		Scanner sc = new Scanner(System.in);

		int n =sc.nextInt();
		int h[]=new int[n];

		int count=0;
		boolean start=false;


		for(int i=0;i<n;++i){
			h[i]=sc.nextInt();
		}

		for(int num=1;num<=100;++num){
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		}

		System.out.println(count);


	}
} public class Main{

	public static void main(String args[]){

		Scanner sc = new Scanner(System.in);

		int n =sc.nextInt();
		int h[]=new int[n];

		int count=0;
		boolean start=false;


		for(int i=0;i<n;++i){
			h[i]=sc.nextInt();
		}

		for(int num=1;num<=100;++num){
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		}

		System.out.println(count);


	}
} Main
import java.util.Scanner;


public class Main{

	public static void main(String args[]){

		Scanner sc = new Scanner(System.in);

		int n =sc.nextInt();
		int h[]=new int[n];

		int count=0;
		boolean start=false;


		for(int i=0;i<n;++i){
			h[i]=sc.nextInt();
		}

		for(int num=1;num<=100;++num){
			start=false;
			for(int i=0;i<n;++i){
				if(h[i]!=0){
					if(start==false){
						start =true;
						++count;
					}
					h[i]=h[i]-1;
				}
				else start=false;
			}
		}

		System.out.println(count);


	}
}