Clam Chowder

2-6 1/2 oz cans minced clams
1 cup diced onions
1 cup diced celery
2 cups diced, cooked potatoes
1 1/2 teaspoons salt
1/2 teaspoon sugar
1/2 teaspoon pepper
3/4 cup butter
3/4 cup flour
2 cups half and half (cream)
2 cups milk

Saute onions and celery in butter.  Add flour, mix well.  Add milk. Cook on medium heat stirring constantly until thick.  Add potatoes, salt, sugar, pepper, and clams.